Electron attachment to isolated molecules as a probe to understand mitochondrial reductive processes

This chapter describes the complementary experimental techniques Electron Transmission Spectroscopy and Dissociative Electron Attachment Spectroscopy, two of the most suitable means for investigating interactions between electrons and gas-phase molecules, resonance formation of temporary molecular negative ions, and their possible decay through the dissociative electron attachment (DEA) mechanism. The latter can be seen as the gas-phase counterpart of the transfer of a solvated electron in solution, accompanied by dissociation of the molecular anion, referred to as dissociative electron transfer (DET). DET takes place in vivo under reductive conditions, for instance, in the intermembrane space of mitochondria under interaction of xenobiotic molecules possessing high electron affinity with electrons “leaked” from the mitochondrial respiratory chain. A likely mechanism of the toxic activity of dichlorodiphenyltrichloroethane based on its DEA properties is briefly outlined, and compared with the well-established harmful effects of the model toxicant carbon tetrachloride ascribed to reductive dechlorination in a cellular ambient. A possible mechanism of the antioxidant activity of polyphenolic compounds present near the main site of superoxide anion production in mitochondria is also briefly discussed.